News

Initially Launching a Novel, High-Affinity BCMA CAR Targeting NK
Cell Development Candidate for Multiple Myeloma, with an Option for up
to Five Additional CAR Targeting Sequences

SAN DIEGO--(BUSINESS WIRE)--Mar. 4, 2019--
NantKwest,
Inc.(Nasdaq:NK),
a leading clinical-stage Natural Killer (NK) cell based therapeutics
company, and ProMab Biotechnologies today announced the establishment of
a worldwide license to a B-Cell Maturation Antigen (BCMA) targeted
antibody sequence for multiple myeloma along with an option for up to
five undisclosed targeting sequences for exclusive use in the
development of chimeric antigen receptor (CAR) based NK cell therapies.

“We are pleased to announce this collaboration with ProMab
Biotechnologies, marking another milestone for NantKwest in the
development of targeted, next generation, NK cell therapeutics against
multiple myeloma and other cancers,” said Dr. Patrick Soon-Shiong, CEO
of NantKwest. “With an estimated five-year survival rate of around 49%
and accounting for 10% of all hematological malignancies, patients with
multiple myeloma are in critical need for more effective treatment
options. We believe, NantKwest’s CAR-based NK cell therapy may represent
a much needed new treatment option for these patients. We eagerly
anticipate growing our relationship with ProMab and accelerate the
development of these new and innovative, next-generation off-the shelf,
CAR-based NK cell therapies.”

“ProMab’s strategic focus is on the development of monoclonal antibodies
and their application in cell therapy through the integration of next
generation sequencing, bioinformatics, high-throughput screening
technologies, and novel in vitro in vivo validation tools. This new
partnership allows NantKwest to leverage the breadth of our monoclonal
antibody generation and validation platform, our human antibody library
screening capabilities, together with NantKwest’s strong NK cell
engineering, manufacturing, and clinical expertise,” said John Wu,
President and CEO of ProMab Biotechnologies. “We look forward to working
together with the NantKwest team to more rapidly bring new NK cell
therapeutics into the clinic.”

Multiple Myeloma

Multiple myeloma is a debilitating blood cancer that while treatable is
usually considered incurable, resulting in over 100,000 deaths annually
on a worldwide basis. Representing a significant unmet medical need,
without treatment, survival is typically less than one year. Even with
treatment, which typically involves the use of chemotherapy, steroids,
targeted therapy, and in some cases, stem cell transplant, survival
often can only be extended to 4 to 5 years. The BCMA protein is
important in B cell development and preferentially expressed in mature B
lymphocytes. BCMA protein is also believed to be involved in the
development of multiple myeloma and other blood cancers and is an
important target for drug development.

About NantKwest Inc.

NantKwest, a
member of the NantWorks ecosystem of companies, is an innovative
clinical-stage immunotherapy company focused on harnessing the power of
the innate immune system by using the natural killer cell to treat
cancer and virally induced infectious diseases.

NantKwest is uniquely positioned to implement precision cancer medicine,
with the potential to change the current paradigm of cancer care.
Natural Killer (NK) cells are a safeguard in the human body designed to
recognize and detect cells under stress due to cancer or viral
infection. NantKwest’s “off-the-shelf” activated NK cell platform is
designed to destroy cancer and virally infected cells from the body. The
safety of our NK cells as well as their activity against a broad range
of cancers has been tested in phase I clinical trials in Canada and
Europe as well as in multiple phase I and II clinical trials in the
United States. In addition to being a universal cell-based therapy that
does not require individualized patient sourcing or matching, our NK
cell products have been largely administered in the outpatient setting
as an “off-the-shelf” living drug.

With the capacity to grow active killer cells as a living cancer
therapy, our NK cells have been designed to induce cell death against
cancers and virally infected cells by several mechanisms, including:
innate killing, whereby all of our NK platforms recognize the stress
proteins typically found on cancer cells, which, upon binding, release
toxic granules to immediately kill their targets; antibody-mediated
killing with our haNK® platform, which are NK cells engineered to
express antibody receptors that can bind to therapeutic antibody
products, thereby enhancing the cancer cell killing effect of that
antibody. All three modes of killing (innate, antibody-mediated, and CAR
directed killing) are employed by our t-haNK™ platform, which is an
innovative combination of our aNK, haNK® and taNK® platforms in a single
product.

Our haNK®, and t-haNK™ platforms have been designed to address certain
limitations of CAR T-cell therapy including the capability to infuse
cell therapy in an outpatient setting which allows for potential
reduction of risk for serious cytokine storms and protracted serious
adverse events. In Phase I and II clinical trials in patients with late
stage cancer, our NK cells have been administered as an investigational
outpatient infusion safely with greater than 300 infusions to date at a
dose of 2 billion cells per infusion.

By leveraging an integrated and extensive genomics and transcriptomics
discovery and development engine, together with a pipeline of multiple,
clinical-stage, immuno-oncology programs, we believe NantKwest is
uniquely positioned to be the premier immunotherapy company and
transform medicine by delivering living drugs in a bag and bringing
novel NK cell-based therapies to routine clinical care.

ProMab Biotechnologies is a biotechnology company located in Richmond
California, that focuses to develop and commercialize mouse, rabbit,
human monoclonal antibodies as well as chimeric antigen receptor-T Cell
(CAR-T) products. ProMab’s CAR-T platform covers both hematological and
solid cancers with intensive in vitro and in vivo pre-clinical
validation designed for safer and better treatment. As a CRO in the
immunology field for 18 years, ProMab offers standard laboratory
procedures and animal studies for the antibody discovery through the
integration of the newest techniques in antibody library construction,
next generation sequencing, unique humanization modeling,
high-throughput screening, and artificial intelligence analysis
systems. ProMab aims to out-license antibodies validated in CAR-T
therapy or bring the CAR-T technologies to the early stage market of
clinical study. ProMab has partnered with top biotechnology startups,
medical institutions, and pharmaceuticals to advance the development of
cell therapies as well as bispecific antibodies across multiple cancers.
For more information, visit www.promab.com.

Forward-Looking Statements

This press release contains forward-looking statements within the
meaning of the Private Securities Litigation Reform Act of 1995.Forward-looking
statements include statements concerning or implying the Company will be
successful in improving the treatment of cancer.Risks and
uncertainties related to this endeavor include, but are not limited to,
obtaining FDA approval of our NK cells as well as other therapeutics as
part of the NANT Cancer Vaccine platform as a cancer treatment.

Forward-looking statements are based on management's current
expectations and are subject to various risks and uncertainties that
could cause actual results to differ materially and adversely from those
expressed or implied by such forward-looking statements. Accordingly,
these forward-looking statements do not constitute guarantees of future
performance, and you are cautioned not to place undue reliance on these
forward-looking statements.

These and other risks regarding our business are described in detail
in our Securities and Exchange Commission filings, including in our
Quarterly Report on Form 10-Q for the quarter ended September 30, 2018.These forward-looking statements speak only as of the date hereof,
and we disclaim any obligation to update these statements except as may
be required by law.

The Natural Killer Cell platform consists of investigational agents that are restricted by federal law to investigational use only.
The Natural Killer Cell platform is being investigated in multiple clinical trials across tumor sites.

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